JP2015217406A - Hot press steel component, manufacturing method for the same, and hot- pressing press die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot press steel component having embossment and excellent rigidity and strength, a manufacturing method for a hot press steel component which can be manufactured by one process and is excellent in shape giving performance with spring back suppressed, and a hot-pressing press die which can be used for this manufacturing method.SOLUTION: A hot press steel component 1 comprises an embossment part 10 and flat parts 20 and 21. Although the embossment part 10, the flat part 20, and the flat part 21 are integrally formed, the embossment part 10 and the flat part 20 are folded to be continuous at a fold part 10x, and the flat part 20 and the flat part 21 at a fold part 20x, and then the hot press steel component 1 has a hat-shaped side face as the whole. The manufacturing method comprises hot press working of such a hot press steel component 1. A hot-pressing molding die performs press molding, emboss molding, and annealing in the die.

Description

The present invention relates to a hot-pressed steel part, a manufacturing method thereof, and a hot-press press die.
More specifically, a hot-pressed steel part having embossing formed by hot pressing and having excellent rigidity and strength, which can be manufactured in a single process, and has excellent shape imparting properties with suppressed springback. The present invention relates to a method for manufacturing a steel part, and a hot press die that can be used in this method.

2. Description of the Related Art In recent years, in the automobile industry and the like, weight reduction of vehicles and parts has been achieved by reducing the thickness of a steel plate to be used in order to improve fuel consumption and electricity consumption. However, in general, the rigidity is lowered and the strength is lowered by reducing the plate thickness.
Therefore, conventionally, steel sheets have been embossed cold in order to achieve both weight reduction and rigidity by reducing the plate thickness. Further, in order to improve the strength, hot pressing of a steel plate or cold pressing of a so-called high-tensile material (high-tensile steel) has been performed.

  However, hot pressing of steel sheets for improving strength is expensive in equipment costs, and in cold pressing of high-tensile materials, the shape retention of the molded product is not sufficient due to the spring back of the high-tensile materials. Therefore, it is necessary to estimate the springback and perform molding. In some cases, it is also necessary to correct the shape, which is disadvantageous from an economic point of view because the degree of freedom in designing the molded product is low and man-hours are required.

  In addition, in order to achieve both weight reduction and rigidity and strength by reducing the thickness of the steel sheet, the steel sheet that has been cold embossed in advance is pressed with a press die having a predetermined cooling medium passage, and is sufficiently baked with the cooling medium. There has been proposed a pressure forming method for forming a steel plate having an emboss by inserting (see Patent Document 1).

International Publication No. 2010/084864

However, in such a prior art, the embossing previously formed may be pressurized and the shape may collapse. In addition, since the emboss is formed in advance on the entire steel plate, other members must be joined and attached at the emboss formation site, the strength of joining and attachment is reduced, and the attachment of other members is inferior.
Furthermore, the steel plate must be embossed in advance and then hot pressed, which increases the number of man-hours and is not sufficient for manufacturing efficiency.

  The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide a hot-pressed steel part having embossing and excellent rigidity and strength in one step. An object of the present invention is to provide a method for manufacturing a hot-pressed steel part that can be manufactured and has excellent shape imparting properties with suppressed spring back, and a hot-press press die that can be used in this manufacturing method.

  As a result of intensive studies to achieve the above-mentioned object, the present inventor has found that the above-mentioned object can be achieved by performing embossing and hot pressing on a desired part together, and to complete the present invention. It came.

  That is, the hot-pressed steel part of the present invention is a part having an embossed part and a flat part, wherein the embossed part and the flat part are formed by hot pressing a steel plate.

  The method for producing a hot-pressed steel part according to the present invention is a method for producing a hot-pressed steel part having an embossed part and a flat part. The steel sheet is heated, and the heated steel sheet is press-formed, embossed and quenched in a press die.

  Furthermore, the press die for hot pressing of the present invention has an emboss forming portion for forming an embossed portion in a hot-pressed steel part, and a flat forming portion for forming a flat portion, and a cooling medium that comes into contact with a portion other than the molding surface. It is characterized by providing.

  According to the present invention, since embossing to a desired part and hot press processing are performed together, a hot press steel part having embossing and excellent rigidity and strength, this can be manufactured in one step, It is possible to provide a method for manufacturing a hot-pressed steel part that is suppressed in spring back and has excellent shape imparting properties, and a hot-press press die that can be used in this manufacturing method.

It is a perspective view which shows one Embodiment of the hot press steel components of this invention. It is a perspective view which shows other embodiment of the hot-pressed steel components of this invention. It is a perspective view which shows other embodiment of the hot-pressed steel components of this invention. It is a perspective view which shows other embodiment of the hot-pressed steel components of this invention. It is a perspective view which shows other embodiment of the hot-pressed steel components of this invention. It is a top view which shows the example of an embossing pattern. It is a top view which shows the example of an embossing pattern. It is a top view which shows the example of an embossing pattern. It is a top view which shows the example of an embossing pattern. It is a perspective explanatory view showing each process in a manufacturing method of hot press steel parts of the present invention.

<Hot-pressed steel parts>
Hereinafter, the hot-pressed steel part of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of a hot-pressed steel part according to the present invention.
In FIG. 1, this hot-pressed steel part 1 includes an embossed portion 10 and flat portions 20 and 21.

  The embossed portion 10, the flat portion 20, and the flat portion 21 are integrally formed, but the embossed portion 10 and the flat portion 20 are bent at a bent portion 10x, and the flat portion 20 and the flat portion 21 are bent at a bent portion 20x. It is continuous, and the hot-pressed steel part 1 has a hat-shaped side surface as a whole.

  In the hot-pressed steel part 1, the embossed portion 10 has a windmill-shaped embossed pattern 11 projecting upward from the surface thereof, but the flat portions 20 and 21 have a flat surface.

In the present embodiment, the end portion of the embossed pattern 11 is in contact with the bent portion 10x. Thus, by forming the embossed pattern 11 over a wide range up to the boundary with the flat portion 20, the rigidity improvement provided by the embossed formation is improved. The effect can be maximized.
The weakest part of the emboss is the emboss apex. If the embossed pattern 11 is formed in a wide range up to the boundary with the flat part 20 in this way, the emboss apex is arranged in the bent part 11x. In the example, there is an advantage that bending can be easily performed.

The reason why the embossed pattern 11 can be formed up to the border with the flat part 20 is that the hot-pressed steel part of the present invention is embossed in the hot-pressing process, and the embossed pattern has a high shape freezing property. is there.
On the other hand, in the conventional cold embossing of high-tensile material, so-called springback occurs, and high shape freezing property cannot be obtained, and the rigidity improvement effect by emboss formation cannot be fully enjoyed.

In this hot-pressed steel part 1, the flat part 21 is formed flat, and is used for welding with other members or casings (not shown), particularly spot welding.
Also in this case, unlike the conventional high-tensile cold working, it is not necessary to consider the spring back for the bending work, so that the joining accuracy can be improved and a strong joining can be realized.

Although not shown, the flat portion 21 can be provided with a bolt hole or the like, and can be used for fastening by bolting with other members or a casing.
Also in this case, unlike the conventional case, it is not necessary to consider the spring back for the bending process, so that the fastening accuracy can be improved and the firm fastening can be realized.

Next, FIGS. 2 to 5 show other embodiments of the hot-pressed steel part of the present invention.
In addition, the same code | symbol is attached | subjected to the member and element which is practically the same as the member and element demonstrated above, and the description is abbreviate | omitted.

  FIG. 2 shows an embodiment in which the embossed pattern 12 of the embossed portion 10 in the hot-pressed steel part 2 has a cylindrical shape protruding upward in the figure. In this case also, the end of the embossed pattern 12 is bent. The above-mentioned advantages can be obtained.

  In the embodiment shown in FIG. 3, the embossed pattern 13 of the hot-pressed steel part 3 has a turtle shell shape that is recessed downward in the figure, and in this case also, the end of the embossed pattern 13 is in contact with the bent portion 10x. The above advantages can be obtained.

  In the embodiment shown in FIG. 4, the embossed pattern 14 of the hot-pressed steel part 4 has a square shape protruding upward in the figure, and these are arranged like a checkered pattern. The portion can be brought into contact with the bent portion 10x, and the above advantages can be obtained.

In the embodiment shown in FIG. 5, the embossing pattern is the same as that of the embodiment of FIG. 1, but the embossed part is bent, and an embossed part 16 continuous with the embossed part 10 and the bent part 10 y is formed. . As described above, in the present invention, the embossing pattern and the shape freezing property of the bending process are good, so that it is easy to bend the embossed part.
Moreover, the embossed part 10 is provided with a transport hole 15, and it is easy to transport the hot-pressed steel part 5 to another place. Such a conveyance hole can also be formed precisely because of its good shape freezing property.

  6 to 9 show examples of the emboss pattern. In the present invention, any emboss pattern can be used satisfactorily, and the above-described advantages can be obtained.

<Hot-pressed steel part manufacturing method and hot-press mold>
Next, the manufacturing method of the hot press steel parts of this invention is demonstrated.
The method for producing a hot-pressed steel part according to the present invention is a method for obtaining a hot-pressed steel part as described above. The raw steel sheet is heated, and the heated raw steel sheet is pressed, embossed, and baked in a mold. Put in.

In FIG. 10, each process in an example of the manufacturing method of the hot press steel components of this invention is shown.
As shown in the figure, in the manufacturing method of the present invention, the raw steel 100 is first transported to the heating furnace 30 and heated to a desired temperature to hold the temperature.
Next, the heated raw steel plate 100 is conveyed to a press die 40 (forming die), processed into a desired shape (bending processing) with heat, and desired embossing is performed. Further, after quenching in the press mold 40, the mold is released to obtain the hot pressed steel part 1.

  Here, as the raw steel plate 100, a steel plate type including at least one alloy element such as manganese (Mn), chromium (Cr), molybdenum (Mo), and boron (B) can be used. A typical steel plate thickness is 1.0-2.0 mm. Moreover, the raw steel plate is typically heated at 800 to 1000 ° C.

Note that the press die 40 has a forming surface for imparting a desired shape to the raw steel plate. Typically, bending press processing and embossing are performed on the forming surface, and an emboss forming portion is formed on the forming surface. A flat part forming part is provided.
Quenching in the press die 40 can be performed by a normal cooling means (not shown), for example, by bringing a cooling medium (not shown) into contact with the upper die 41 and the lower die 42. Specifically, a plurality of water pipes may be embedded in the upper mold 41 and the lower mold 42.
In such a case, the cooling medium may not be in direct contact with the raw steel plate 100.

As mentioned above, although this invention was demonstrated by some embodiment, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention.
For example, the embossed pattern can adopt not only a convex shape or a concave shape but also both concave and convex shapes. Further, the arrangement can be changed as appropriate according to the required rigidity.

The hot-pressed steel part of the present invention, its manufacturing method and mold are usable in various industries, and particularly useful in the machine industry such as the automobile industry.
For example, the hot-pressed steel parts of the present invention can be suitably used for automobile dash cloth, sill, heat insulator, parcel (PSHELF), rear panel, dash panel, floor, seat panel, and the like.

1-5 Hot-pressed steel parts 10, 16 Embossed portion 10x, 10y Bent portion 11-14 Embossed pattern 15 Transport hole 20, 21 Flat portion 20x Bent portion 30 Heating furnace 40 Press die 41 Upper die 42 Lower die 100 Raw material steel sheet

Claims (8)

  A hot-pressed steel part having an embossed part and a flat part, wherein the embossed part and the flat part are formed by hot pressing a steel plate.   The hot-pressed steel part according to claim 1, wherein the embossed part and the flat part are continuous at a bent part.   The hot-pressed steel part according to claim 2, wherein an end portion of the emboss pattern existing in the embossed portion is in contact with the bent portion.   The hot-pressed steel part according to any one of claims 1 to 3, wherein the flat part includes a joint part used for welding with another member or an attachment part used for fastening. In manufacturing hot-pressed steel parts with embossed parts and flat parts,
A method of manufacturing a hot-pressed steel part, comprising heating a raw steel plate and press-molding, embossing and quenching the heated raw steel plate in a mold.   6. The method of manufacturing a hot-pressed steel part according to claim 5, wherein the quenching is performed by bringing a cooling medium into contact with a surface other than the molding surface of the press die.   A hot-press mold for hot-pressed steel parts, comprising: an emboss forming portion for forming an embossed portion on a raw steel plate; a flat forming portion for forming a flat portion; and a cooling means.   The hot press molding die according to claim 7, wherein the cooling means is a cooling medium in contact with a portion other than the molding surface formed by the emboss forming portion and the flat forming portion.

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